"Our top priority is to provide the best possible experience for customers in maintaining and protecting their systems. This month, we discovered a last minute issue that could impact some customers and was not resolved in time for our planned updates today.

"After considering all options, we made the decision to delay this month's updates. We apologize for any inconvenience caused by this change to the existing plan."

I've asked Microsoft if there's any more information about the reasons for the delay and how long this delay is likely to last. No word back so far.

Update: A Microsoft spokesperson said the company had nothing to say beyond the statement above. Meanwhile, some of my contacts are saying they are hearing a problem with Microsoft's build system might be the reason for today's patch delay.

This may be the first time ever since it began releasing security patches on the second Tuesday of each month that Microsoft didn't actually deliver any on the specified day. (Anyone remember anything like this previously?)

Microsoft modified its patching schedule last year. But The second Tuesday of the month remains the regularly scheduled Patch Tuesday. Any security-specific fixes for Office are slated to show up on that day, along with the bulk of the rest of Microsoft's security and non-security patches and fixes across its product line.